Clauses in the U.S. Constitution that guarantee religious freedom are among the most prolific sources of litigation before the U.S. Supreme Court, former U.S. Solicitor General Rex E. Lee said Tuesday.

Lee spoke at Brigham Young University to several hundred students and faculty members. He said that in years past religious issues were not prominent among constitutional cases, but that has changed."The religion clauses have definitely made up for lost ground over the last 40 years," he said. "The safest prediction of all is that the religion clauses will continue to be a fruitful and fascinating source of litigation."

The clauses are contained in the First Amendment to the Constitution. They guarantee free exercise of religion and prohibit the government from establishing a state religion.

As cases involving these rights come before the Supreme Court, justices have had to interpret constitutional rights. Lee said the wall separating church and state is not strictly upheld, and if it were, Americans might lose some of the traditions they take for granted, like having Christmas designated a national holiday and using references to deity in the Pledge of Allegiance and on coins.

"These kinds of references are the kinds of things that would probably not be permitted if the wall (eparating church and state) were high and impenetrable," he said.

The two central religion clauses have come into conflict with one another in some recent cases, and when that happens, free exercise usually wins over establishment, he said. For instance, in a recent case, a college had prohibited religious groups from using its facilities to avoid violating separation between church and state. A religious group sued on grounds of discrimination, and the court found in its favor.

Lee, founding dean of the BYU law school, was solicitor general from 1981 to 1985 and was assistant attorney general in the civil division of the Department of Justice from 1975 to 1977. He was a law clerk to Supreme Court Justice Byron R. White in 1963 and became an associate in the law firm Jennings, Strouss, Salmon and Trask in Phoenix in 1964. He joined the firm as a partner in 1967.

He now practices with Sidley and Austin, arguing almost exclusively before the Supreme Court. He combines his private practice with teaching constitutional law at BYU as the George Sutherland professor of law.